In the context of this description, the word “ear” is taken to refer to the entire organ, consisting of the outer ear, the ear canal, the mid-ear and the inner ear. Human sound perception takes place in the inner ear and protection from hearing damage can be provided by attenuating sound as it travels through the ear canal, before it reaches the mid-ear.
In the field of hearing protection, an ear plug is commonly used to provide this attenuation. Generally, hearing protection is useful in noisy environments, for instance, for ground personnel in airports etc. It becomes essential, and is often required by law, in environments with noise levels above 80 dB. Also, in sub 80 dB environments, hearing protection can increase the comfort level, for instance when exposed to noise levels above 65 dB for longer periods of time.
In addition to providing protection against deafening or unpleasant noise levels, conventional hearing protectors may also block essential information such as voice communication, warning signals etc, even to such an extent that a protected person becomes uneasy wearing the protectors and decides to discontinue their use, potentially causing discomfort or hearing damage. To overcome these problems, various approaches have been suggested. Among these, European patent publication EP0333298 discloses an acoustic plug where a user can adjust the attenuation level by an adjustable insert that is placed in the acoustic channel. This ear plug needs to be manually adjusted by the user, by selecting and placing an insert with the desired amount of attenuation. In practical use, this ear plug essentially provides protection with fixed amount of attenuation, since a user will or cannot adjust instantaneously to variations in noise level. The present invention aims to provide an improved ear plug, offering a continuously, automatically adjusted amount of attenuation to adequately attenuate excessive noise levels while optimizing the perception of relevant sounds.